I had a slightly different use-case for these - I had a last-minute need to get audio from an outside event's soundboard into a smartphone for livestreaming where an audio cable connection was not practical.
I ordered two, which arrived very quickly, and then it was a simple case of pairing them as transmitter and receiver. They worked perfectly for the duration of the three hour event. They are small enough to tuck out the way, and light enough not to adversely effect the smartphone 3-axis gimbal.
Update: Note this device only supports aptX (in addition to aptX Low Latency) in transmit mode. It does not support base level aptX in receive mode, only SBC. Pairing two of these together has 202 ms latency. If you need it, there are competing products that claim to support aptX Low Latency also in receive mode.